The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 08, 1995
Filed:
Jul. 20, 1994
Applicant:
Inventor:
Ronald A Carpio, Austin, TX (US);
Assignee:
Sematech, Inc., Austin, TX (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
2041531 ; 20415312 ; 204409 ; 204406 ; 204434 ; 204412 ; 422 681 ; 422 81 ; 422 8201 ; 422 8202 ;
Abstract
A feedback control system for providing automated control of multi-component chemical concentrations in a hydrogen peroxide/ammonia (SC-1) aqueous bath or in a hydrogen peroxide/hydrochloric (SC-2) aqueous bath used for semiconductor processing. A sample from the liquid bath is routed to two sensors. Three separate schemes for determining concentrations of the two chemicals in the bath are provided by the selection of one of three separate pairs of sensors. A processor is used to monitor and control the chemical makeup of the bath.